Access All AlternatesThis feature makes all variations of a selected character accessible. This serves several purposes: An application may not support the feature by which the desired glyph would normally be accessed; the user may need a glyph outside the context supported by the normal substitution, or the user may not know what feature produces the desired glyph. Since many-to-one substitutions are not covered, ligatures would not appear in this table unless they were variant forms of another ligature.
Contextual AlternatesIn specified situations, replaces default glyphs with alternate forms which provide better joining behavior. Used in script typefaces which are designed to have some or all of their glyphs join.
Contextual SwashThis feature replaces default character glyphs with corresponding swash glyphs in a specified context. Note that there may be more than one swash alternate for a given character.
Discretionary LigaturesReplaces a sequence of glyphs with a single glyph which is preferred for typographic purposes. This feature covers those ligatures which may be used for special effect, at the user's preference.
DenominatorsReplaces selected figures which follow a slash with denominator figures.
FractionsReplaces figures separated by a slash with 'common' (diagonal) fractions.
KerningAdjusts amount of space between glyphs, generally to provide optically consistent spacing between glyphs. Although a well-designed typeface has consistent inter-glyph spacing overall, some glyph combinations require adjustment for improved legibility. Besides standard adjustment in the horizontal direction, this feature can supply size-dependent kerning data via device tables, "cross-stream" kerning in the Y text direction, and adjustment of glyph placement independent of the advance adjustment. Note that this feature may apply to runs of more than two glyphs, and would not be used in monospaced fonts. Also note that this feature does not apply to text set vertically.
Standard LigaturesReplaces a sequence of glyphs with a single glyph which is preferred for typographic purposes. This feature covers the ligatures which the designer/manufacturer judges should be used in normal conditions.
NumeratorsReplaces selected figures which precede a slash with numerator figures, and replaces the typographic slash with the fraction slash.
Scientific InferiorsReplaces lining or oldstyle figures with inferior figures (smaller glyphs which sit lower than the standard baseline, primarily for chemical or mathematical notation). May also replace lowercase characters with alphabetic inferiors.
Stylistic Set 1In addition to, or instead of, stylistic alternatives of individual glyphs (see 'salt' feature), some fonts may contain sets of stylistic variant glyphs corresponding to portions of the character set, e.g. multiple variants for lowercase letters in a Latin font. Glyphs in stylistic sets may be designed to harmonise visually, interract in particular ways, or otherwise work together. Examples of fonts including stylistic sets are Zapfino Linotype and Adobe's Poetica. Individual features numbered sequentially with the tag name convention 'ss01' 'ss02' 'ss03' . 'ss20' provide a mechanism for glyphs in these sets to be associated via GSUB lookup indexes to default forms and to each other, and for users to select from available stylistic sets.
SubscriptThe "subs" feature may replace a default glyph with a subscript glyph, or it may combine a glyph substitution with positioning adjustments for proper placement.
SuperscriptReplaces lining or oldstyle figures with superior figures (primarily for footnote indication), and replaces lowercase letters with superior letters (primarily for abbreviated French titles).
TitlingThis feature replaces the default glyphs with corresponding forms designed specifically for titling. These may be all-capital and/or larger on the body, and adjusted for viewing at larger sizes.
